I'm currently following this guide on making an Arduino OpenTherm Controller. After finding almost all of the parts without any issue; my only question remained with the "PNP transistor" named in the hardware list. As someone who is new to electronics, this did not mean much to me, so I sought out an exact name for this transistor. Elsewhere on the webpage I found this image:
As you can see, it names the transistor as a BC558A. However, after searching online for this transistor I either found few or no results. On the other hand, I found many BC558B transistors like this one so I ordered a pack. After initially thinking that because no specific "PNP transistor" was named; any sort would do, I began to reconsider this which is why I am asking for help.
My question is: Will the BC558B transistor I have ordered function in the same way in the circuit? If not, what would a reasonable alternative to the BC558A transistor be, seeing as it is very hard to find online?
Thank you in advance for any help.